124 
P.N. WYSE JACKSON 
Table 2 Quantitative comparison between Carboniferous Hexites species (dimensions in mm). 
AR BW 
H. paradoxus sp. nov. 5-8 0.37-0.72 
H. triangularis Shulga-Nesterenko, 1955 6 0.18-0.38 
H. quadrangularis Dunaeva, 1974 8 0.52 
i 
Data from original sources. 
| 
| 
| 
AD1 AD2 AS1 AS2 
0.20-0.43 0.08—-0.22 0.09—-0.42 0.13-0.40 
0.17 0.08 
Genus NEMATOPORA Ulrich, 1888a | 
H. paradoxus is only the third Hexites species to be described and | 
first outside of the CIS (former Soviet Union). It differs from the / 
type species H. triangularis Shulga-Nesterenko 1955 in having a- 
larger branch width, a variable number of autozooecial rows (five to 
eight and not the consistent six of the latter), no peristomes, andy 
acanthostyles in interapertural areas. It bears a close resemblance to { 
H. quadrangularis Dunaeva 1974, which has 8 rows of autozooecia. } 
However, H. paradoxus shows some morphological differences: 
branches are often thicker, autozooecial apertures are larger, ellipti-i 
cal to oval in shape, and are spaced considerably further apart. On i 
the basis of these morphological differences H. paradoxus is erected | 
as a new species (Table 2). | 
0.16 0.12 0.18 0.15 
STRATIGRAPHICAL RANGE. Lower Carboniferous (Viséan—Asbian). | 
DISTRIBUTION. Carrick Lough and Sillees River, County Ferman) 
agh, Ireland. 
TYPE SPECIES. Trematopora minuta Hall, 1876 by original desig- 
nation, from the middle Silurian of Waldron, Indiana, U.S.A. 
REVISED DIAGNOSIS. Arthrostylid with delicate, erect, dichoto- 
mously branching zoarium. Branches straight, circular to sub-circulat 
in cross-section. Autozooecia arranged in four to ten longitudinal, 
rows, either completely around branches or concentrated on one side 
of branch. Interapertural areas smooth with acanthostyles developed 
along ridges. Autozooecial apertures are oval to rhombic, dorsally, 
flared. 
—— 
i} 
STRATIGRAPHICAL RANGE. Middle Ordovician—Lower Permian. 
DISTRIBUTION. British Isles, Europe, North America, the CIf 
(former Soviet Union), Asia. 
Nematopora hibernica sp. nov. Figs 3b, 6—7,8) 
HOLoTYPE. BMNH PD9430; Upper part of the Glencar Lime) 
stone (Viséan, Asbian), Carrick Lough, County Fermanagh. | 
| 
Figs 4—5 Hexites paradoxus sp. nov. Upper part of the Glencar 
Limestone (Viséan, Asbian), Carrick Lough, County Fermanagh. 4, 
BMNH PD9410 (holotype); 4a, colony fragment comprising a thin 
slender octagonal to circular-shaped branch; autozooecia are arranged 1 
distinct longitudinal rows divided by strong flexous ridges, and their 
apertures are oval in shape, x30; 4b, detail of 4a showing autozooecial | 
apertures and intervening ridges showing the disposition of small stylet: 
on the crest of ridges, x150. 5, BMNH PD9414 (paratype), reverse 
surface showing longitudinal groove, x12. 
Figs 6,7 Nematopora hibernica sp. nov. Upper part of the Glencar 
Limestone (Viséan, Asbian), Carrick Lough, County Fermanagh. 6, 
BMNH PD9430 (holotype); 6a, small colony fragment showing 
bifurcation of branches, and regular arrangement of autozooecial 
apertures in offset rows on obverse surface, x20; 6b, detail showing 
distal growing tip of branch and pyriform autozooecial apertures 
separated by thin interapertural walls patterned by a single row of smal’ 
stylets, x120. 7, BMNH PD9442 (paratype), reverse surface showing 
longitudinal rows of small nodes, x14. 
